Pushthrough-type cartridge belt link with a bolt actuated cartridge retaining latch



Oct. 13, 1964 R. H. COLBY 3, 5

PUSHTHROUGH-TYPE CARTRIDGE BELT LINK WITH A BOLT ACTUATED CARTRIDGE RETAINING LATCH Filed July 13. 1961 Fi j l INVENTOR.

II' 'AL RishnrELHLulh 1 @m A a J @W United States Patent O 3,152,512 PUSHTEROUGH-TYPE CARTGE BELT LINK WITH A BOLT ACTUATED CARTRIDGE RE- TAINING LATCH Richard H. Colby, South Hadley, Mass, assignor to the United States of America as represented by the Secretary of the Army Filed July 13, 1961, Ser. No. 123,906 2 Claims. (Cl. 89-35) (Granted under Title 35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

This invention relates to firearms and more particularly to cartridge belt links for supplying cartridges thereto.

In modern ordnance, cartridges have been made available in which the projectile is provided with a fragile windshield which would be dangerously damaged if supplied to a firearm by the conventional cartridge belt link and feeding system wherein the projectile is left unprotected in the link and is subject to impact during transfer from the link to the barrel chamber. This cartridge, too, has very little force remaining, after propulsion of the projectile, to actuate the operating and feeding mechanisms of the firearm.

It is, therefore, one object of this invention to provide a link which substantially encircles such a fragile cartridge along the entire length thereof to provide protection therefor.

It is another object of this invention to provide such a link which requires negligible force for shipping the cartridge therefrom.

It is still another object of this invention to provide such a link wherein the cartridge is held against radial displacement by an encircling retainer and is held against longitudinal displacement by a bolt actuated latch.

It is a further object of this invention to provide in cooperation with such a link gun structure for pushing the cartridge from the link into the barrel and returning the fired case to the link.

It is a still further object of this invention to provide such a link which is simple in design, rugged in construction and positive in its functions.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

FIG. 1 is a fragmentary, longitudinally, cross-sectioned view of a firearm receiver showing a cartridge indexed in position to be stripped from the engaging link by the firearm bolt;

FIG. 2 is a view taken along line 22 of FIG. 1;

FIG. 3 is a view taken along line 33 of FIG. 2; and

FIG. 4 is a fragmentary, perspective view of the rear end of the link.

Shown in the figures is a machine gun 12 which is supplied with cartridges 14 by means of a cartridge belt 16 composed of a plurality of links 18 articulately joined together by pintle pins 20 which are inserted through interengaging loops 22 on the links. Cartridges 14 are each provided with a case 23 which is cylindrical in configuration and is provided around the base with an annular groove 24 that forms an extractor rim 26.

Machine gun 12 includes a receiver 28 in the front end of which there is mounted a barrel 30. A bolt 32 is slidingly disposed in receiver 28 for longitudinal displacement between a recoil and a battery position responsive to discharge forces. Bolt 32 includes a breechblock 34 which carries a firing pin 35 and is provided with an integral flange 36 extending longitudinally along the bottom. Flange 36 of inverted T-configuration in crosssection and is received by a mating slot 38 in the bottom of receiver 28 to slidingly support bolt 32 for reciprocation between the recoil and battery positions. A rib 39 extends longitudinally along the top of bolt 32. Provided in the front end of breechblock 34 is a laterally disposed T-slot 40 which is formed to slidingly receive the rear end of cartridge 14 and engage case 23 to bolt 32 through the interengagement of the T-slot with extractor rim 26.

Belt 16 is moved through receiver 28 in a feedway 42 by means of a feeding mechanism having a feed pawl 44 which functions responsive to cyclic operation of machine gun 12 to progressively advance the belt along the feedway. A pair of holding pawls 46 holds the belt 16 against reverse displacement in feedway 42. Feedway 42 is disposed laterally through receiver 24 between the breech end of barrel 30 and the position of the front end of bolt 32 when in the recoil position and includes a portal 48 which projects from the left side of receiver 42. Belt 16 is guided through feedway 42, as hereinafter described, by a pair of longitudinally spaced rails 50 which are of inverted T-configuration in cross-section. Rails 51 are fixed to the ceiling of the feedway and are disposed to guide belt 16 so that cartridges 14 become engaged with T-slot 40 in bolt 32 as they are moved along feedway 42 into position to be transferred into barrel 30.

Each of the links 18 includes a cylindrical retainer 52 which has an inside diameter substantially the same as that of case 23 and a length slightly larger than cartridge 14 so that the cartridge is totally inclosed thereby and is held against radial displacement without resilient force. Retainer 52 is interrupted by a longitudinal mouth 56 which is wide enough to receive the vertical section of T-flange 36 so as to permit displacement of breechblock 34 in and out of retainer 52 during reciprocation of bolt 32. Retainer 52 is pressed outwardly diametrically opposite mouth 56 to form a longitudinal channel 54 of inverted U-cross-section. Provided laterally through channel 54 is a pair of grooves 55 which matingly receive rails 50 whereby link 18 is slidingly supported and guided by the rails during passage through feedway 42. Portal 48 positions links 18, during passage therethrough, for engaging grooves 55 therein with rails 50. Loops 22 are integrally formed, as by press methods, in retainer 52.

As cartridge 14 is held by retainer 52 without resilient pressure therebetween, a latch 58 is provided in link 18 to hold the cartridge against longitudinal displacement therein. Latch 58, which is fabricated from spring steel, is received by channel 54 and is fixed to the top crosssection thereof by a rivet 57. The free end of latch 58 is provided with a cam portion 64 of arcuate cross-section which forms a convex surface 66 which faces cartridge 14 in retainer 52. Latch 58 is also arranged to be springbiased downwardly so that the cam portion 64 thereof presses against extractor rim 26 a section of which is received by a transverse slot 59 in the cam portion to hold the engaged cartridge 14 against longitudinal displacement. When link 18 carrying cartridge 14 is moved into stripping position, convex surface 66 contacts rib 39 in bolt 32 to cam latch 58 upwardly to free the rim from slot 59 for release of the cartridge, and the latch is held in the release position during reciprocation of the bolt by the sliding contact of cam portion 64 with the top of the rib. Provided in the rear end of link 18 is a clearance 60 for the section of breechblock 34 above T-slot 40 when the link is moved laterally to and from the stripping position thereof.

Thus, during operation of machine gun 12, belt 16 is advanced by feed pawl 44 to successively index cartridges 14 therein at a stripping position between the breech end of barrel 30 and bolt 32 which, during the actuation of the belt, is in its recoil position. As a cartridge 14 is advanced to the stripping position, the base thereof is received by T-slot 49 in bolt 32. At the same time, rib 39 on top of bolt 32 contacts convex surface 66 of latch 58 so that the latch is cammed upwardly and slot 59 is disengaged from extractor rim 26. Thereby, when link 18 is indexed for stripping, cartridge 14 is engaged to bolt 32, through the cooperation of extractor rim 26 with T-slot 40, and is released from latch 56 for displacement from the link. After link 18 is indexed, the operating mechanism (not shown) of machine gun 12 continues the operating cycle by actuating bolt 32 from the recoil to the battery position to move breechblock 34 through retainer 62 and thereby carry the cartridge linearly therefrom into barrel 30, without impact with any gun structure, for discharge by firing pin 35. Bolt 32 is actuated to the recoil position responsive to the discharge and pulls fired case 23 from barrel 30 back into link 18. When bolt 32 reaches recoil position, the operating mechanism functions to actuate feed pawl 44 for advancing belt 16 another pitch. Thereby, the previously fired case 23 is moved out of engagement with T-slot 40 in bolt 32 and latch 58 is simultaneously moved clear of rib 39 and thereby freed for reengaging extractor rim 26 of the case.

From the foregoing it is clearly apparent that there is provided herein a link which protects the engaged cartridge against damage while retained therein and which requires negligible force for the stripping of the cartridge therefrom and there is also provided cooperating gun structure whereby the cartridge is stripped from the link and carried longitudinally by the bolt into the barrel chamber so that the cartridge projectile will not be subject to impact with gun structure during such transfer.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claims are intended to include such variations.

I claim:

1. In a gun, the combination including a receiver, a barrel mounted in the front end of said receiver, a breechblock disposed in said receiver for longitudinal reciprocation between a battery and a recoil position, a feedway extending laterally through said receiver between the breech end of said barrel and the front end of said breechblock when in the recoil position, a cartridge having a case with an extractortrirn .around the base thereof, a link including a retainer for holding said cartridge against radial displacement and without-resilient pressure, a latch fixed within said retainer so as to press resiliently against said rim and a lateral slot formed in said latch to receive a section of said rim for holding said cartridge against longitudinal displacement in said link, means for guiding said link laterally through said feedway to a stripping position between said barrel and said breechblock, a T-slot formed in the front end of said breechblock so as to engage said case at said extractor rim when said cartridge is moved to the stripping :position, and cooperating means on said latch and said breechblock for actuating said latch to a position to release said rim when said link is moved to the stripping position and for releasing said latch to re-engage said rim when said case is moved away from the stripping position.

2. The combination as defined in claim 1 wherein said cooperating means on said latch and said breechblock include a convex surface on said latch and a longitudinal rib disposed on said breechblock for contact by said convex surface during displacement of said link to the stripping position to cammingly actuate said latch to the rim releasing position as said case is engaged by said T-slot, said rib being arranged to extend along said breechblock so as to be in sliding contact with said cam portion for holding said latch in the rim releasing position during longitudinal reciprocation of said breechblock, and said rib being arranged so as to release said latch for re-engagement with said rim when said case after being relinked by said breechblock is displaced away from the stripping position.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN A GUN, THE COMBINATION INCLUDING A RECEIVER, A BARREL MOUNTED IN THE FRONT END OF SAID RECEIVER, A BREECHBLOCK DISPOSED IN SAID RECEIVER FOR LONGITUDINAL RECIPROCATION BETWEEN A BATTERY AND A RECOIL POSITION, A FEEDWAY EXTENDING LATERALLY THROUGH SAID RECEIVER BETWEEN THE BREECH END OF SAID BARREL AND THE FRONT END OF SAID BREECHBLOCK WHEN IN THE RECOIL POSITION, A CARTRIDGE HAVING A CASE WITH AN EXTRACTOR RIM AROUND THE BASE THEREOF, A LINK INCLUDING A RETAINER FOR HOLDING SAID CARTRIDGE AGAINST RADIAL DISPLACEMENT AND WITHOUT RESILIENT PRESSURE, A LATCH FIXED WITHIN SAID RETAINER SO AS TO PRESS RESILIENTLY AGAINST SAID RIM AND A LATERAL SLOT FORMED IN SAID LATCH TO RECEIVE A SECTION OF SAID RIM FOR HOLDING SAID CARTRIDGE AGAINST LONGITUDINAL DISPLACEMENT IN SAID LINK, MEANS FOR GUIDING 